Modeling and Data Analysis 📊 | Fall 2025

How can we use models and data to understand and predict the world around us?

Lucy Lai

lai@ucsd.edu

Hi everyone, I’m a new faculty member at UCSD and excited to be teaching COGS 109 this quarter! In this course, we’ll explore different ways to model and understand data, while building practical skills that are useful for research, industry, and beyond. You’re always welcome to come to my office hours to ask questions or just say hello. I’m looking forward to a great quarter together!

Important Course Info

TAJiesen Zhang
PLAsParinita Saha & Johny Nguyen
ReaderZhicheng Wang
LecturesMWF, 9-9:50am @ CENTR 113
Discussion• W, 2-2:50pm @ WLH 2113
• F, 4-4:50pm @ WLH 2207
• F, 5-5:50pm @ WLH 2207

Office Hours

Prof. Lai• W, 2:30-3:30 (walk-in), 3:30-4pm (book only) @ CSB 244/Zoom
• Th, 4:30-5:30pm (book only) on Zoom
Jiesen ZhangDuring all discussion sections
Johny NguyenDuring W, 2pm discussion sections and W, 12-1pm on Zoom (book)
Parinita SahaDuring F, 4pm discussion section and F, 3-4pm on Zoom (book)

Course Schedule

Week 0

Sep 26 (F)
LEC 0 Course overview and expectations 🎥
Slides
📖 Readings: ISLP Ch. 1
DISC No section this week
🚨 If you missed today’s class, please see this announcement

Week 1 — Intro to Statistical Learning

General
🛝 Week 1 — all slides
🚨 Week 1 Reminders
#FinAid Please submit this short survey to confirm student activity for the quarter! (Required for all students)
Submit
Sep 29 (M)
LEC 1 What is statistical learning? 🎥
Slides
📖 Readings: ISLP Ch. 2.1
HW 1 released!
Details
💡 How to fix the webclicker issue
Oct 1 (W)
LEC 2 Assessing model accuracy 🎥
Slides
📖 Readings: ISLP Ch. 2.2
DISC 2pm @ WLH 2113
Slides
Oct 3 (F)
LEC 3 Data exploration 🎥
Slides
📖 Readings: ISLP Ch. 2.3
DISC 4pm & 5pm @ WLH 2207
Slides
Group project Guidelines and rubric released
Details
Quiz 1 released! due M, Oct 6 @ 11:59pm
Submit
Syllabus quiz due 11:59pm
Submit
Pre-course survey due 11:59pm
Submit
HW 1 due 11:59pm
Submit

Week 2 — Regression

General
📊 FINAL PROJECT GROUPS 📊
🛝 Week 2 — all slides
💡Resources:
🚨 Week 2 - Monday reminders
🚨 Week 2 - Friday reminders
Oct 6 (M)
LEC 4 Simple linear regression 🎥
Slides
📖 Readings: ISLP Ch. 3.1
Quiz 1 due 11:59pm
Submit
HW 2 released!
Details
Oct 8 (W)
LEC 5 Multiple linear regression 🎥
Slides
📖 Readings: ISLP Ch. 3.2
DISC 2pm @ WLH 2113
Slides
Oct 10 (F)
LEC 6 Other considerations in regression 🎥
Slides
📖 Readings: ISLP Ch. 3.3
DISC 4pm & 5pm @ WLH 2207
Slides
Quiz 2 released! (optional) due M, Oct 13 @ 11:59pm
Submit
HW 2 due 11:59pm
Submit
#FinAid due TODAY Please submit this short survey to confirm student activity for the quarter! (Required for all students)
Submit

Week 3 — Classification

General
🛝 Week 3 — all slides
🚨 Week 3 - Monday reminders
🚨 Week 3 - Friday reminders
Oct 13 (M)
EXAM 1 covers Weeks 1 & 2
  • You may bring one 8.5x11” cheat-sheet, one-sided
  • To prepare: review HW 1&2, Quiz 1&2, webclicker questions from Week 1&2, check out the exam question bank.
HW 3 released!
Details
Quiz 2 (optional) due 11:59pm
Submit
Oct 15 (W)
LEC 7 Logistic Regression 🎥
Slides
📖 Readings: ISLP Ch. 4.1-4.3
Group project Checkpoint 1 due Mon, Oct 20
Submit video / Submit self-grade
DISC 2pm @ WLH 2113
Slides
Oct 17 (F)
LEC 8 Generative classification models 🎥
Slides
📖 Readings: ISLP Ch. 4.4
DISC 4pm & 5pm @ WLH 2207
Slides
Quiz 3 released! due Mon, Oct 20
Submit
HW 3 due 11:59pm
Submit

Week 4 — Resampling

General
🛝 Week 4 — all slides
🚨 Week 4 - Friday reminders
💡Resources:
Oct 20 (M)
LEC 9 Cross-validation 🎥
Slides
📖 Readings: ISLP Ch. 5.1
Group project Checkpoint 1 due 11:59pm
Submit video / Submit self-grade
HW 4 released!
Details
Quiz 3 due 11:59pm
Submit
Oct 22 (W)
LEC 10 Bootstrap methods & predictive modeling workflow 🎥 (podcast audio error, please see this re-recorded lecture)
Slides
📖 Readings: ISLP Ch. 5.2
DISC 2pm @ WLH 2113
Slides
Oct 24 (F)
LEC 11 Generative classification models (cont’d) & kNN 🎥
Slides
📖 Readings: ISLP Ch. 4.4 & 2.2
DISC 4pm & 5pm @ WLH 2207
Slides
Quiz 4 released! (optional) due Mon, Oct 27
Submit
HW 4 due 11:59pm
Submit

Week 5 — Model Selection & Regularization

General
[🛝 Week 5 — all slides]
🚨 Week 5 - Monday reminders
🚨 [Week 5 - Friday reminders]
Oct 27 (M)
EXAM 2 covers Weeks 3 & 4
  • You may bring one hand-written 8.5x11” cheat-sheet, one-sided
  • To prepare: review HW 3&4, Quiz 3&4, webclicker questions from Week 3&4, check out the exam question bank.
Quiz 4 (optional) due 11:59pm
Submit
HW 5 released! HW5 is very short ~2hrs with NO coding portion, because I want everyone to focus their coding efforts on their group checkpoint 2 this week! We will also address most of it directly in lecture.
Details
Oct 29 (W)
LEC 12 Subset selection and model selection metrics 🎥
Slides
📖 Readings: ISLP Ch. 6.1
DISC 2pm @ WLH 2113
Oct 31 (F)
LEC 13 Regularization (shrinkage) 🎥
Slides
📖 Readings: ISLP Ch. 6.2
DISC 4pm & 5pm @ WLH 2207
Quiz 5 released! due Mon, Nov 3
Submit
HW 5due 11:59pm
Submit

Week 6 — Non-Linear Regression

General
[🛝 Week 6 — all slides]
🚨 [Week 6 - Monday reminders]
🚨 [Week 6 - Friday reminders]
💡Resources:
Nov 3 (M)
LEC 14 Polynomial regression; Step & basis functions 🎥
Slides
📖 Readings: ISLP Ch. 7.1-7.3
Group project Checkpoint 2 due 11:59pm
Submit video / Submit self-grade
HW 6 released!
[Details]
Quiz 5 due 11:59pm
Submit
Nov 5 (W)
LEC 15 Splines & smoothing 🎥
Slides
DISC 2pm @ WLH 2113
📖 Readings: ISLP Ch. 7.4-7.5
Nov 7 (F)
LEC 16 Generalized additive models 🎥
Slides
📖 Readings: ISLP Ch. 7.7
DISC 4pm & 5pm @ WLH 2207
Quiz 6 released! (optional) due Mon, Nov 10
Submit
HW 6
Submit

Week 7 — Tree-Based Methods

Nov 10 (M)
EXAM 3 covers Weeks 5 & 6
  • You may bring one hand-written 8.5x11” cheat-sheet, one-sided
  • To prepare: review HW 5&6, Quiz 5&6, webclicker questions from Week 5&6, check out the exam question bank.
Quiz 6 (optional) due 11:59pm
Submit
Nov 12 (W)
LEC 17 Decision trees 🎥
Slides
📖 Readings: ISLP Ch. 8.1
DISC 2pm @ WLH 2113
Nov 14 (F)
LEC 18 Bagging, random forests, boosting 🎥
Slides
📖 Readings: ISLP Ch. 8.2
DISC 4pm & 5pm @ WLH 2207
Quiz 7 released! due Mon, Nov 17
Submit
HW 7 due 11:59pm
Submit

Week 8 — Unsupervised Learning

Nov 17 (M)
LEC 19 Principal components analysis (PCA) 🎥
Slides
📖 Readings: ISLP Ch. 12.1-12.2
Quiz 7 due 11:59pm
Submit
Nov 19 (W)
LEC 20 Factor analysis 🎥
Slides
📖 Readings: TBD
DISC 2pm @ WLH 2113
Nov 21 (F)
LEC 21 K-means & hierarchical clustering 🎥
Slides
📖 Readings: ISLP Ch. 12.4
DISC 4pm & 5pm @ WLH 2207
Quiz 8 released! due Mon, Nov 24
Submit
HW 8 due 11:59pm
Submit

Week 9 — Neural networks

Nov 24 (M)
LEC 22 Simple neural networks 🎥
Slides
📖 Readings: ISLP Ch. 10.1-10.2
Group project Checkpoint 3 due 11:59pm
Submit video / Submit self-grade
Quiz 8 due 11:59pm
Submit
Nov 26 (W)
LEC 23 Convolutional neural networks 🎥
Slides
📖 Readings: ISLP Ch. 10.1-10.3
DISC No section this week
Nov 28 (F)
THANKSGIVING BREAK — No class
DISC No section this week
Quiz 9 released! (optional) due Mon, Dec 1
Submit
HW 9 due 11:59pm
Submit

Week 10 — Final project presentations

Dec 1 (M)
EXAM 4 covers Weeks 7, 8, & 9
Quiz 9 (optional) due 11:59pm
Submit
Dec 3 (W)
Group project expo
DISC No section this week
Dec 3-5 (W-F)
Final group project presentations
DISC No section this week
SET evaluations due Sat, Dec 6 at 8am